1. Field of the Invention
The present invention relates to a vacuum cleaner, and particularly to a damper formed at a suction side of a motor built in the vacuum cleaner, for preventing the motor from being damaged.
2. Description of the Related Art
A vacuum cleaner is generally classified into a canister vacuum cleaner and an uptight vacuum cleaner. Particularly, the upright vacuum cleaner includes a main body, a nozzle unit and a handle that are integrally formed, so the vacuum cleaner itself is moved when a user pushes or pulls a handle by gripping it. At this time, dusts on the floor are sucked through the nozzle to clean the floor. A general configuration of such an uptight vacuum cleaner is already well known from many documents, so its detail description is omitted. Meanwhile, a suction fan for sucking outer air and a motor providing a rotational force for rotation of the suction fan are built in a main body of the vacuum cleaner.
In operation of the vacuum cleaner, as the motor built in the main body rotates, rotational force of the motor is transferred to the suction fan so that a negative pressure is generated by the suction fan. The negative pressure interacts with the nozzle unit, so that outer air is sucked through the nozzle unit, foreign particles contained in the sucked outer air are filtered by a dust collection assembly, the filtered air is introduced into the suction fan and the motor, and is then exhausted.
Meanwhile, when a lot of foreign particles are accumulated in the dust collection assembly or fabric, such foreign particles may prevent outer air from being sucked into the motor. If the outer air is not sucked into the motor, the motor is overheated, resulting in damage to the motor or a shortened life span of the motor.
Considering the above problems, a damper is installed at a suction side of the motor. When an excessive negative pressure is generated in a passage of the suction side of the motor, the damper sucks the outer air.
However, in case where an excessive negative pressure as generated in the damper, the damper may be separated from its support and fall into an inside of the main body of the vacuum cleaner. The falling damper damages the motor. Also, since all air of the suction fan is sucked through an installation hole of the damper, outer air may not be sucked through the nozzle unit.
Further, in case the damper falls into the inside of the main body of the vacuum cleaner and an object such as a bar is sucked through the installation hole of the damper, the vacuum cleaner may be damaged in an initial stage of the operation. Furthermore, if a user's finger falls into the installation hole, the user may be injured.
Moreover, if the damper does not have a suction space of a proper size, the amount of air by-passed through the damper is decreased, so that the functions of the damper may be not performed properly.